ABSTRACT
The liver is an important, multifunctional organ with major roles in the synthesis of plasma proteins, detoxification and excretion of exogenous and endogenous potentially toxic substances, and in digestion and absorption through the secretion of bile. It receives a dual blood supply from the hepatic artery and portal vein and drains through the sinusoids via the hepatic veins to the inferior vena cava. The portal venous system draws blood from the intestine and therefore everything that is absorbed from the gut passes through the liver before entering the systemic circulation. Failure of this metabolic guardian function in liver disease is an important determinant of clinical symptoms. Bile passes in the opposite direction to blood flow, from the canaliculus formed between two liver cells to the bile ducts. Three structures – the hepatic arteriole, portal venule and biliary duct – form the so-called portal triad that is embedded within loose connective tissue; this is one of the key structural landmarks at a microscopic level in the liver. The boundary between the portal tract (the fibrovascular connective tissue and the portal triad) and adjacent hepatocytes is called the limiting plate. The intrahepatic portal tree originates from the surrounding developing liver and this process involves complex control of cell proliferation,
Key Points
• The liver is a large metabolically active organ involved in homeostasis and detoxification.
